Increasing the strength of paper with vinyl sulfonium polymers



United States Patent 3,130,117 INCREASING THE STRENGTH OF PAPER WITH VINYL SULFONIUM POLYMERS Charles G. Humiston, Frederick J. Meyer, and Duane L. Kenaga, all of Midland, Mich, assignors to The Dow Chemical Company, Midland, Mich, a corporation of Delaware No Drawing. Filed Mar. 13, 1961, Ser. No. 95,015 7 Claims. (Cl. 162-168) This invention relates to the use of water-soluble homopolymers and copolymers of certain vinyl sulfonium compounds as beater additives to improve the physical properties of cellulosic and lignocellulosic articles such as paper, hardboard and insulation board.

In the making of paper, hardboard, insulation board and the like various non-fibrous materials may be added to the stock at or beyond the beater prior to article formation. Such materials are known as beater additives and are employed to improve the properties of the finished product such as dry and wet strength, water repellancy, dimensional stability, rot and mildew resistance and rodent repellancy. Certain additives may increase machine speed, reduce loss of fines, reduce refining costs, permit the use of a larger percentage of inert fillers, or allow an increase in the use of less expensive short fibered pulp.

Beater additives may be added at the beater, or at other points in the process up to and including the head box. In certain machines it is possible to introduce the beater additives at other points between the refiner and the head box, such as the machine chest, stuff box, fan pump or Jordan box.

Strong cellulosic articles are obtained through the use of long-fibered Woods in the preparation of the pulp. However, the supply of soft woods which are long fibered is insuflicient to meet the growth demands of the pulp and paper industry and the use of hardwoods, which are short fibered, is increasing. t is, therefore, a desideratum of the art, to provide additives which will increase both the dry and wet strength of articles manufactured from cellulosic and lignocellulosic materials.

We have now found that such articles may be obtained by adding from about 0.025 to 5.0, preferably from about 0.1 to 3.0 weight percent, dry fiber basis, of one or more Water-soluble homopolymers and copolymers of Vinyl sulfonium compounds to the fiber slurry at or beyond the beater prior to article formation. The homopolymers used in the present invention may be represented by the general formula wherein R is selected from the group consisting of hydrogen and alkyl radicals containing from 1 to 6 carbon atoms, X is an organic sulfur-containing radical selected from the group consisting of (A) sulfides of the formula, R SR wherein R and R each represents a member of the group consisting of (1) alkyl radicals containing from 1 to 6 carbon atoms, (2) haloalkyl radicals containing from 1 to 6 carbon atoms, (3) hydroxyalky'l radicals containing from 1 to 6 carbon atoms; (4)

0 2) n(1Ht IH2(3oH wherein n is an integer from 1 to 4 inclusive; (5)

0 (CHZ)nCHOH OH wherein n is an integer from 1 to 4 inclusive; (6)

(CH CH O) CH CH Ol-I wherein m is an integer from 1 to 5; (7) C,,H ,,COOH; s c u cooc n 9 C H COO alkali metal; and (10) C I-i CONH wherein n in substituents (7), (8), (9) and (10) is an integer from 1 to 5 with the total number of carbon atoms in each of the substituents (7), (8), (9), and (10) not exceeding 6, and where the total number of carbon atoms of the R and R groups attached to a common sulfur atom doe not exceed 18 and (B) cyclic thio compounds selected from the group consisting of tetrahydrothiophene, hydroxy substituted tetrahydrothiophene, halo substituted tetrahydrothiophene, alkyl substituted tetrahydrothiophene where allryl refers to groups containing from 1 to 5 carbon atoms, tetrahydrothiopyran, and 1,4-oxathiane; and Y is an anion such as carbonate, oxalate, phthalate, succinate, dihydrogen phosphate, fluoride, benzoate, chloride, nitrate, acetate, sulfate, bromide, iodide and the like.

The monomers useful in preparing the polymers to be used in this invention are made by contacting a vinylbenzyl halide with an organic sulfur containing compound in the presence or absence of a solvent or nonsolvent liquid medium. The polymers may be produced by subjecting the monomers to the polymerization methods conventionally used with free radical catalyzed aqueous systems, i.e., emulsion-, and solution polymerization in the presence of actinic light, ultra-violet irradiation, gamma radiation, azo catalysts and peroxides.

In preparing the monomers of this invention, a vinylbenzyl haiide such as the chloride, bromide, or iodide is reacted with an organic sulfur-containing compound as defined heretofore. Theoretical molar equivalents of the vinylbenzyl halide and the sulfur-containing compound ordinarily are used, although from percent up to 200 percent stoichiometric amounts of the organic sulfurcontaining compounds can be used. An excess of about 200 percent of the stoichiometric value in some cases promotes the formation of the vinylbenzyl sulfonium halide monomer. This excess of the sulfur containing reactant is recoverable from the reaction mixture. If the reactants are liquid, preparation of the monomer can be carried out without use of a solvent, but solvents such as water, nitromethane, methanol, ethanol, acetonitrile and the like can be used. The reaction can be carried ether.

or mixtures thereof.

far-.3

out at temperatures from about room temperature up to about 100 C.; but reaction temperatures from about 30 to about 80 C. are preferred. The reaction normally will be carried out at substantially atmospheric pressure, but superatmospheric pressure sufiicient to prevent loss of volatile reactants can be employed. A minimum reaction time of about 2 to about 4 hours results in formation of certain of the monomeric sulfonium compounds. However, this reaction time will vary with the different molecular species and reaction times of 24 hours or more can be employed.

The vinylbenzyl sulfonium monomers, as produced, will have a halide anion. If desired this halide form of the monomer can be converted in a conventional manner to any one of a number of common anionic forms such as carbonate, nitrate, sulfate, acetate and the like by passing a solution of the monomer into contact with an anion exchange resin in the proper salt form.

Preparation of the homopolymers and/or copolymers is conveniently carried out by polymerizing the monomeric sulfonium compound with or without another polymerizable monomer such as acrylamide, polyolefins, acrylic acid, vinylaromatic monomers, acrylates and methacrylates, acrylonitrile, trimethyl(ar-vinylbenzyl) ammonium chloride, and the like in an emulsion or solution in the presence of vinyl polymerization catalyst such as ultraviolet light, gamma radiation, azo catalysts, peroxides, and the like for a period of time ranging from 4 hours to two weeks or more.

In some instances the polymeric products useful in the present invention may be prepared by other routes such as by introducing a halomethyl group into an aromatic polymer substrate and thereafter reacting .with a thio- Because of the dilficulty in obtaining a uniform distribution of the introduced halomethyl groups and and the difiiculty of obtaining an effective reaction of such products with the thioether, this route is not generally desirable.

The homopolymers and copolymers may be lightly cross-linked with any of the conventional cross-linking agents such as diviuylbenzene (DVB), the divinyl ether of diethylene glycol, ethylene glycol diacrylate, ethylene glycol, diacrylate, ethylene glycol dimethacrylate, glycerol trimethacrylate, dialkyl itaconate, diallyl, maleate, dially fumarate, diisopropenyl diphenyl, the close homologues, equivalents, and the like of the foregoing, When prepared in an emulsion and when in a swelling medium, the polymers are referred to herein as microgels. The polymers, especially the microgels often advantageously can be prepared by emulsion polymerization of the vinylbenzyl halide followed by reaction with the desired sulfur-containing compound, although this method is less effective in some cases than the above described procedure.

Polymers useful in the present invention include homopolymers of vinylbenzyl bis(2-hydroxyethyl)sulfonium chloride, vinylbenzyl methylthetin, vinylbenzyl-Z-hydroxyethanolthetin, vinylbenzyl methyl(3-carboxy-3-hydroxy propyl)sulfonium hydroxide, inner salt; vinylbenzyl bis(2- carboxyethyDsulfonium hydroxide, inner salt; vinylbenzyl methyl 2-hydroxyethyl sulfonium chloride and the like.

The molecular weight of the homopolymers and copolymers used in the present invention is not critical. It is necessary for the polymer to bear a multiplicity of positive charges so it will adsorb effectively on the paper pulp. Linear polymers having a molecular weight up to 100,000 or more and lightly cross-linked polymers and microgels having molecular-Weights from 100,000 up to 200, or more, million have been found to be equally effective in improving the wet and dry strength, water resistance, flexural strength, etc. of the finishedcellulosic article.

As little as 0.025 weight percent, dry fiber basis, of the sulfonium homopolymers or copolymers will produce a marked improvement in the physical properties of the resulting cellulosic article although from 0.1 to 3.0 weight percent is preferable. A greater amount may be used if desired, but is usually disadvantageous for economic con siderations.

With the use of the additives of this invention it is possible to reduce the beating time and still maintain a desired level of dry bursting strength in the finished product. Alternatively, a higher level of dry bursting strength may be obtained than would be obtainable by using increased beating time alone. As increased beating does not increase wet strength, it is possible, with the use of the additives of this invention, to reduce heating time while maintaining a desired level of dry bursting strength and at the same time increasing wet strength with no decrease in the tearing resistance.

The pH of the pulp slurry to be treated is not critical, and may vary from acid to alkaline. A pH in the range of from about 4.0 to 10.0 is preferably used.

In order to attain maximum strength improvement with the sulfonium additives of this invention it is necessary to completely cure the resin in the product by heating and drying.

The additives of the present invention are equally effective when no alum is used as an inorganic flocculant and when up to 10 percent alum is added.

The present invention may be better understood by reference to the following examples which are not to be construed as limiting.

EXAMPLE I Unbleached mixed hardwoods soda pulp was beaten in a Valley beater to a freeness of 360 ml. (Canadian standard freeness). Five grams of the beaten pulp were dis persed in approximately 2 liters of water. Various concentrations of three microgels were added to the pulp slurry from dilute solutions (-0.1 to .5 percent in water). After stirring 3 minutes the slurry was diluted further with tap water and hand sheets made up. All sheets were dried for 30 minutes at 110 C. Bursting strength was determined according to standard TAPPI procedures. Results are as follows. I

The effect of beating time on unbleached soda pulp and cotton linters with and Without the additives of the present invention is shown in Tables II and III. The sulfonium polymer is poly[ar vinylbenzyl bis( 2 hydroxyethyl)sulfonium]chloride and is essentially linear. The mic-rogel is poly(dimethyl[ar-vinylbenzyl] sulfonium chloride) which is crosslinked with 0.06 weight percent divinylbenzene. At each freeness aliquots of pulp slurry containing 5 grams of pulp were removed and tested. Handsheets were made up and wet and dry burst and dry tear were determined by standard test methods, i.e. T APPI standard T220m53.

Table II Canadian Percent Percent Beating Standard Dry Increase Wet Wet Run Treatment Time Freeness Burst in Burst Burst Burst/ (Min) (ML) Factor over Con- Factor Dry trol Control 21 552 10.1 21 552 23. 3 130. 7 5. 3 52. 5 32 460 18. 3 O 32 460 34. 5 88.5 9. 5 51. 9 40 396 24. 3 O 40 396 41. 7 71.6 11.9 49.0 50 288 31. 4 8 1% sulfom'unn- 50 288 48. 2 53. 5 15.1 48.1 9 Control 60 186 36. 6 0 1% sulf0nium 60 186 49. 4 35.0 16.2 44.3

Table III EFFECT OF BEATING TIIVIE ON COTTON LINTERS such as pH, concentration, molecular weight, type of pulp, addition of alum, and the use of various copolymers and homopolymers Within the scope of this invention. For these experiments the pulp Was prepared by adding sheet.

Canadian Percent Percent Beating Standard Dry Increase Wet Wet Tear Run Treatment Time Freeness Burst in Burst Burst Burst/ Factor (Min) (ML) Factor over Factor Dry Control Control 19 487 6. 9 0 73. 9 19 487 14. 9 159. 4 6. 7 97. 1 93. 8 306 11.4 4.1 87.2 40 306 20. 7 81. 6 9. 3 81.6 98.0 40 306 18. 4 168 12. 9 1% sulfonium- 60 168 25. 4 1% microgel 60 168 19. 9 Control 76 14. 0 1% slllfoniurn 80 76 21. 8 1% rnicrogel 80 76 23.0

Tables IV through XI illustrate the eifects of variables 360 grams of air-dry pulp and 23 liters of water to a Aliquots containing 5 grams of pulp were removed for each hand- Two liters of water were added to the aliquot, and the test material added with stirring. The dilute slurry was added to the sheet mold and the handsheets 55 prepared according to a modification of TAPPI standard T205-m53. The sheets were oven dried, conditioned at least 48 hours at 21 C. and 62 percent relative humidity, and tested for dry burst, tensile and tear according to TAPPI standard T220-m53. Wet bursting strength was determined after soaking the test samples in deionized water for 4-24 hours. All tests were corrected for basis weight of the papers. Unless otherwise noted the pulp used was unbleached hardwood soda pulp. In each case the percent additive is based on dry weight of the pulp.

Table IV EFFECT OF pH ON THE ACTIVITY OF POLY [ar-VINYLBENZYLBIS(2-HYDROXYETHYL) SULFONIUM CHLORIDE] (ESSENTIALLY LINEAR) Percent Percent Dry Increase Wet Wet Breaking Percent Tear Run Treatment pH Burst in Burst Burst Burst/ Length Increase Factor Factor over Factor Dry (Meters) over Control Control Control Control 4. 5 21. 9 0 100 88.1 1% sulfonium. 4. 5 38. 2 74. 4 10. 7 48. 9 530 34. 9 v 0 ControL 7. 0 22. 5 0 0 4, 230 87. 8 1% Su1f0nium 7. 0 38. 6 71. 6 11.1 49 3 5, 840 38. l 94. 7 Control 9. 5 21. 7 0 0 4, 010 89.7 1% sultonium 9. 5 40.0 84. 3 12.6 58. 1 5, 660 41.1 94. 9

Table V EFFECT OF CONCENTRATION Concen- Dry Percent tration Burst Increase Run Treatment of Factor in Additive Burst Weight over (percent) Control 1 Control 22:3 2 Poly ar-viuy1benzy1-bis-(2- 0. 36. 2 62. 3

hydroxyethyl) sulfonium chloride (linear). 3 "do 1. 0 40.0 79. 4 4 d0 1. 5 43.2 93. 7 5 d0 2. 0 41. 3 i 85. 2 6 do 2. 5 42. 2 89.2 7 d0 3.0 41.9 87.9 8 Control 0 28. 9 9 Poly(dimethyl[ar-vinyl-benzyl] 0.1 31. 9 10. 4

sulfonium chloride) with 0.04% divinylbenzene (Microgel). 10 do 0.5 40.1 38. 8 11 d0 1.0 46.5 60.9 12 do 3.0 42. 3 46. 4

Table VI EFFECT OF POLYMER SIZE OF POLY[DIMETHYL(ar VINYLBENZYL) SULFONIUM CHLORIDE] MICROGELS Percent Approximate Burst Increase Run 1% sulfonium polymer 1 Molecular Factor in Burst Weight over Control Control. 21. 3 0.8% DVB 200 1111111011-"- 32. 2 51. d 37.3 75. 34. 9 63. 40. 2 88. 38. 0 78. 38.0 78. 34. 9 63. 0.02% DVB do 36. 3 70. 0. 00% DVB 1.75 million 37.0 73.

0.00% DVB 0.01% DDM 2 1. 36 million. 39.7 86. 0.00% DVB 0.01% DDM 450, 000.-- 39. 2 84. Linear sulionium polymer 100, 000 38. 4 80.

1 Emulsion polymerization of vinylbenzyl chloride followed by reaction with dimethyl sulfide.

2 DVB =divinylbenzene; DDM =dodecylmercaptan. 3 Solution polymerization of sulfoniurn monomer.

Table VII EFFECT OF PULP FURNISH ON BURST Percent 5 Run Furnish Free- Additive Increase ness in Dry Burst 1 Ncwspring 150 1% Poly[ar-vinyl- 33 benzyl-bis(2-hydroiryethyl) sulto- 1O nium chloride].

2. Unbleached soda pulp d 35 3 Mixed hardwoods 86 4 Bleached cotton 97 liutcrs. 5 do 175 1% Poly[din1ethyl)ar- 55 vinyl-benzyDsul- 15 fonium chloride].

0.06% DVB. 6- Unbleached soda pulp. 190 do 25 7 Mixed hardwoods 400 do 90 Table VIII EFFECT OF ALUM ADDITION Weight Percent Percent Dry Increase Wet Run Treatment Alum Burst in Burst Burst Added 1 Factor over Factor Control 7 0 40. 6 11. 9 1. 0 23. 9 e 0 1. 0 41. 4 12.3 3. 0 24. 3 1. 3 3.0 38.1 56. 8 11.0 5. 0 22. 3 1. 3 5.0 39.0 74. 9 12. 7 10. 0 23. 6 1.1 10 1% sulfonium 10.0 38.3 62.3 12.1

fonium chloride].

Table IX HANDSHEETS TREATED WITH COPOLYMERS OF DIMETHYL (ar- VINYLBENZYL)SULFONIUM CHLORIDE AND OTHER LMONOMERS Weight percent Weight Percent other Percent Dry Increase Wet Tear Run Other Monomer Monof Copol- Burst in Burst Burst Factor omer in ymer Em- Factor over Factor copolployed Control ymer 80 l. 0 29. 2 32. 1 3. 3 102. 3 60 1. 0 34.1 54.3 9.5 97.7 1. 0 34. 5 56.1 9.1 101.2 40 0. 67 32. 6 23. 0 6. 9 80 1. 0 46. 8 46. 8 10. 0 101.2 1. 0 39. 7 68. 9 11. 3 97.6 40 1. 0 38.6 64.3 10.9 99. 4 20 1.0 41.3 75.7 11.6 101.2 40 0.5 33. 4 26.0 6. 5 V 3 1. 0 39. 7 75.7 11. 4 104. 3 f 5 1. 0 36. 8 62.8 10. 5 103. 4 12 Methylngrethacrylate. 20 1. 0 34. 6 47. 2 7. 8

- 1 (0.04-0.06 percent DVB.)

Table X PROPERTIES OF HANDSHEETS TREATED WITH COPOLYMERS OF BIS (2- HYDROXYETHYL) ar-VINYLBENZYL SULFONIUM CHLORIDE AND e Ammonium=trirnethyl (ar-vinylbenzyl) ammonium chloride.

b Microgel polymer containing 0.04-0.06 weight percent divinylbenzene (DVB).

a Sulioniurn=dimethyl (anvinylbenzyl) sulionium chloride.

Table XI PROPERTIES OF HANDSHEETS TREATED WITH OTHER POLYiNIERS WITHIN THE SCOPE OF THIS INVENTION Percent Percent Percent Weight Dry Increase Wet Wet Run Polymer Per- Burst over Burst Burst/ Burst] cent Factor Control Factor Dry Dry Control Burst Poly[(vinylbenzybbis-(2-hydroxyethyhsultonium chloride]-.- 1. 33.6 54.1 6.5 29.8 19. 3 dO 1. 0 31. 44. 5 4. 0 18. 3 l2. 7

Poly[(vinylbenzyl)methyl-2,3-dihydroxypropylsuliornium chlor' e 1. 0 37. 3 9.4 7. 2 21. 1 19.3 Poly[(vinylbenzyl) -2-hydroxyethyl-2-carbamoylethylsulfom'urn chloride]- 1. 0 32. 3 31. 8 5. 6 22. 9 17. 3 PolyKvinylbenz )methyl-Z-carbarnoylethylsulfonium oride]. 1. 0 31.1 26.9 5.1 20. 8 16. 4 Poly[(vinylbenzyl)methyl-2hydroiqvethylsulionium chloride]. 1. 0 32. 8 33. 9 5. 3 21. 6 16. 2 Poly[(viny1benzyl)methyl(earbarnoylmctnybsulfonium chloride] 1. 0 33. 9 38. 4 6. 9 28. 2 20. 4 Poly (vinylbenzyDmethyl thetin] 1. 0 28.3 6.4 1.6 6. 0 5. 7 (vinylbenzyhethanol thet'm]+alun1 1. 0 34. 6 30. 1 7. 9 29. 7 22. 8 (vinylbenzybmethionium chloride] 1. 0 33.0 1. 5 10.5 31. 3 31. 8 j (vinylbenzyl)-bis-(2 hytlroxyethybsulioninm bicarbonate] 1. 0 26. 7 25.4 2.3 10.0 8.6 1, Poly[(vinylbenzyl)-bis-(2-hydroxyethyl)sulioninm acetate] 1. 0 29. 9 40. 4 3. 3 l4. 3 10.0 13 Poly[(vinylbenzyl)-bis-(2-hytlroxyethyDsulfonium dihydrogenphosphate] 1. 0 27. 0 26. 8 4.1 17.8 15. 2 (vinylbenzyl)-bis-(2 hydroxyethyl)sulionium sulfate] 1. 0 28. 1 31. 9 2. 8 12.2 10.0 (vinylbenzyl)-bis(2-hydrowethyl)sulfonium bromide 1. 0 26. 9 26. 3 2. 7 11.7 10.0 (vinylbenzyl)-bis-(2-hydroxyethy1)sulfoniumfluoride]. 1. 0 2G. 7 25. 4 2.4 10.4 9.0 (vinylbenzyl)-bis(2-hydroxyethyl)sulfonium nitrate] 1. 0 27. 2 27.7 2. 3 10.0 8.5 (vinyloenzyl)-bis( hydroxyethybsulionium benzoate]. 1. 0 26. 8 25.8 2. 5 10. 9 9.3 (vinylbenzyD-his s ydroxyethyhsulfonium phthalate]. 1. 0 29.4 38.0 4. 5 19.6 15.3 (vinyloenzyl)-bis-(2-hydroiryethyl)sulionium carbonate] 1. 0 27. 9 31. 0 3. 4 14. 8 12. 2 (vinylhenzyl)bis-(2-hydroxyethybsulfonium succinate] 1.0 29.0 36. 2 4.3 18.7 14.8 (vinylbenzyD-bis-(J hydrorryethyhsulioniurn oxalate] 1. 0 25. 1 17. 8' 3. 2 13. 9 12.7 (vinylbenzyl)-l:is-(2-hydroiq'ethybsolionium maleatc] 1. 0 29. 9 40. 4 5.0 21. 7 16. 7 j (arvinylbenzyl)tetrahydrothiopheniurn chloride] 1. 0 37. 8 69. 5 11.3 51.1 29. 9

Y (ar-vinylbenzyl) (2(2(2(2(2-hydroxyethoxy)ethoxy)- ethoxy)ethoxy)ethyl) sulfoniurn chloride] 1. 0 29. 2 39.3 5. 5 25. 7 18. 5 Chlorometnylated Polystwene Treated with Dimethyl Sulfide". 1.0 47.8 12.7 11.2 26.4 23.4

Nora-The polymer used in run 26 was prepared by dissolving 10.4 grams of low molecular weight polystyrene (viscosity of soln in toluene at C. equal to 2.0)

in 40.3 grams of chlcromethyl ether with 0.4 mole of catalyst per aromatic nucleus. After 23 hours at room temp. the reaction was killed in MeOH and the polymer isolated. Chlorine analysis indicated about 80% of the henzene rings had CH3C groups attached. 2.24 grams of this polymer was heated at C. with 0.73 gram of dimethyl sulfide and 29.7 ml. of water for about 15 hours.

EXAMPLE III Silvacel 122, a Whole Wood (Douglas fir) fiber, was slurried at a 2 percent consistency (based on oven dry weight of fiber) in Water.

A solution of poly(vinylbenzyl)bis(2-hydroxyethyl) sulfonium chloride was added and the resulting slurry felted in a conventional decide box. After dewatering the mat was placed on a screen in a press at 200 C. Pressure was raised to 300 p.s.i. for /2 minute and finally to 800 p.s.i. for 4 minutes. Various concentrations of the sulfonium polymer were used and the resulting boards were tested for the properties and with the results shown in Table XII. The tests were standard ASTM tests (D1037-52T) modified for size of sample in the case of the Water absorption test.

The soluble fraction was tested as indicated above using a krait pulp.

Table XII EFFECT OF POLYHVINYLBENZYL)BIS(2HYDROXY- ETHYIJSULFONIULI CHLORIDE] OF VARIOUS STRENGTH PROPERTIES OF HARDBOARD LIADE BY WET FORMED-VVET PRESS PROCESS 1 Corrected to 62.4 lb./cu. it. density assuming modulus of rupture changes as the sq. of the density.

1 1 EXAMPLE 1v Following the procedure of Example III fiber was treated with varying percentages of poly[(viny1benzyl) dimethylsulfonium chloride], felted, dewatered, oven dried and cured at 107 C. for 3 hours in a forced draft oven to give a /a inch board of about 14 lb./ cu. ft. density. The products were tested as in Example 111. The results are given in Table XIII Ten gallons of Lady Fair cleansing tissues and 400 ml. of water or of dilute aqueous solution of poly[dimethyl(ar-vinylbenzyl)sulfonium chloride] microgel (hereinafter designated DMBS microgel) were beaten together for thirty seconds in a Waring blender, the resultant slurries of paper fiber were concentrated on a Buchner funnel to give a soft pulp of about paper solids, and this pulp then pressed through a inch glass tube to yield extruded papier-mache samples which were then dried according to two different schedules, the physical appearance noted, and water-resistance determined by placing the samples in beakers of deionized water at room temperature. The results are shown in Table IV. These results show that the control papier-mache samples Wetted rapidly and sank within 15 seconds, degenerating to pulpy slush within 15 minutes, whereas the addition of as little as 0.025% of the DMBS microgel to the water slurry produced samples which were firm (requiring a saw to break them) and which remained firm and dry on eight weeks contact with water.

Table XIV 1 12 of the group consisting of (I) homopolymers having the recurring group V wherein R is selected from the group consisting of hydrogen and alkyl radicals containing from 1 to 6 carbon atoms, X is an organic sulfur-containing compound selected from the group consisting of (A) sulfides of the formula R SR wherein R and R each represents a member of the group consisting of (1) alkyl radicals containing from 1 to 6 carbon atoms, (2) haloalkyl radicals containing from 1 to 6 carbon atoms, (3) hydroxyalkyl radicals containing from 1 to 6 carbon atoms; (4)

where n is an integer from 1 to 4 inclusive; (5

C H COOC H (9) C H COO alkali metal; and (10) C,,H ,,CONH wherein n in substituents (7), (8), (9), and (10) is an integer from 1 to 5 with the total number of carbon atoms in each of the substituents (7), (8), (9), and (10) not exceeding 6, and where the total number of carbon atoms of the R and R groups attached to a common sulfur atom does not exceed 18 and (B) cyclic thio compounds selected from the group consisting of tetrahydrothiophene, hydroxy substituted tetrahydrothiophene, halo substituted tetrahydrothiophene, alkyl substituted tetrahydrothiophene where alkyl refers to groups containing from 1 to 5 carbon atoms, tetrahy- EFFECT OF DMBS MICROGEL ON PAPER-BIACHE Percent D MBS Percent Microgel Initial Drying Appearance of Run polymer water Sched- Dried papier- Water-resistance of papier-mache in water in papier ule mache Slurry macho 1 None 61 b I Weak, crumbly Wets rapidly; slushy pulp within 15 min.

'= II firm Do. 2 0. 025 69 b I firm, hard no visible wetting; firm and substantially dry after eight Weeks in water. 0 II 1o same as above. 3 0. 250 72 b I do same as above. 0 II hard, crumbles same as above.

on sawing.

Microgel polymer containing 0.05% divinylbenzene.

Schedule I: 16 hrs. at C. and 1 atm., then 24 hrs. at 75 C. under vacuum. Schedule II: 16 hrs. at 26 C. and 2 mm., then 24 hrs. at 75 C. under vacuum.

I losic articles which comprises adding from 0.025 to 5.0

drothiopyran, and l-oxa, 4-tetrahydrothiopyran; and Y is an anion from the group consisting of carbonate, 0xalate, phthalate, succinate, di-hydrogen phosphate, fluoride, benzoate, chloride, nitrate, acetate, sulfate, bromide,v

and iodide; (II) copolymer thereof, and (III) copolymers with minor proportions of other ethylenically unsaturated weight percent, dry fiber basis of at least one member 75 monomers to a slurry of cellulosic and lignOCclI l 14 7. The method of claim 1 wherein from about 0.1 to 3.0 weight percent of the polymer is added to the fiber slurry.

References Cited in the file of this patent UNITED STATES PATENTS 2,895,925 Hwa July 21, 1959 2,923,700 Price Feb. 2, 1960 2,947,731 Nummy Aug. 2, 1960 2,989,520 Rutenbert et al. June 20, 1961 3,060,156 Rassweiler et al. Oct. 23, 1962 FOREIGN PATENTS 1,031,228 France Mar. 18, 1953 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 130,117 April 21, 1964 Charles G. Humiston et al.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3, line 55, strike out "and", second occurrence; lines 42 and 43, strike out "ethylene glycol, diacrylate,"; column 7, Table VI, second column, line 13 thereof, for "0.01%" r-ead 0.1% column 8, Table VII, second column, line 1 thereof, for "Newspring" read Newsprint columns 9 and 10, Table XI, second column, line 10 thereof, for "(carbamoylmetnyl)" read (carbamoylmethyl) same Table XI, second column, line 3-0 thereof, for "solfonium" read sulfonium column 10, Table XII, sixth column, in the heading thereof, for "I'nteranl" read Internal column 12, line 69, for "l-oxa, 4-tetrahydrothiopyran" read 1,4- oxathiane column 13, lines 9 and 10, for "poly[(vinyl benzy1)bis(2-hydroxyethyl)sulfonium chloride]" read [vinylbenzyl)bis-(2hydroxyethyl)sulfonium chloride lines 12 and 13, for "poly[(vinylbenzyl)dimethylsulfonium chloride]"' read (vinylbenzyl)dimethylsulfonium chloride same column 13, lines 15' and 16, for "poly[(vinylbenzyl)bis (2-hydroxyethyl)sulfonium chloride]" read (vinylbenzyl)bis (2-hydroxyethyl)sul'fonium chloride Signed and sealed this 20th day of October 1964.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner ofPatents 

1. A METHOD FOR PRODUCING CELLULOSIC AND LIGNOCELLULOSIC ARTICLES WHICH COMPRISES ADDING FROM 0.025 TO 5.0 WEIGHT PERCENT, DRY FIBER BASIS OF AT LEAST ONE MEMBER OF THE GROUP CONSISTING OF (I) HOMOPOLYMERS HAVING THE RECURRING GROUP 